Tankless Water Heaters - Practical for Seasonal Cottage where water is drained?

How would one purge the water in a tankless water heater when winterizing a Northern Michigan cottage? Would it require an impractical disconnection of the tank in and out lines to attach air to it? Would save space but wonder if they are really a good choice. Thanks.

Under each of the tankless water heaters we instll are a valve manifold set. Hot and cold can each be connected to a water hose and allowed to drain the tank by gravity. One could also adapt to air at each valve and blow air backwards on each side. A good plumber should have installed such valves for future needs. As far as if tankless water heaters are a good choice, there are a LOT of factors, both good and bad. Too many people think too highly of them with out knowing or being told the downside too. We put a lot of them in but I always give the customer a sheet of good/bad points before they make up their minds. I don't want to go back with my hat in my hand when something goes wrong and they say "I didn' know that." PS, the tankless isolation kit ad on the right side of the forum is an example of the manifold valve I refered to.

I've actually been thinking about one of these for our cabin. Draining our water heater is somewhat of a pain. I'm also concerned about corrosion from our acidic water. seems like tankless might be the way to go. . .

mcconnellplumbing , educating people on a product they have never used is the best thing to do . kudos to you for doing so , it sure saves a lot of headaches in the future when you hand them a piece of paper in advance that has all the pro and cons.
Seems eventough most people have internet , few consumers take the time to do some homework before hand.

I plumbed my house so I have 2 shutoffs at the lowest point in the system . When I go away for extended periods in the winter , I shut my well pump off drain the pump which has it's own drain valve , open the 2 shutoffs and drain all the pipes in the house.
I also empty the (whole house) water filter and walk away knowing that nothing will freeze.
It takes me 5 minutes to do all of the above.
When I return , I close the 2 the shutoffs and the valve on the pump , prime the pump by topping it up with some water, and I'm back in business in 5 minutes.
10 years and all is fine in Canadian sub-zero weather.
I used 3/4 inch flexible metal tubes with their own fittings and seals on the ends to hook up my tankless water heater , which makes lifes easier on the initial install and if I want to remove it later.
Cheers............................................................Vin.